DE2942744C2 - Polyacetal resin composition excellent in heat resistance and surface machinability - Google Patents

Description

2. polyacetal resin composition according to claim 1, characterized in that the metal of group II des Periodic table is calcium, magnesium or barium

3. polyacetal resin composition according to claim 1 or 2, characterized in that the salt of the metal of Group II of the Periodic Table has an average particle size of about 0.1 to 4.0 µm

4. polyacetal resin composition according to claim 1 to 3, characterized in that the salt of the metal of group II of the periodic table calcium carbonate with an average particle size of about 1.25 µm

5. polyacetal resin composition according to claim 1 to 4, characterized in that the alkyl ester of Acrylic acid or methacrylic acid is the methyl ester or ethyl ester

Plastics are generally very chemically resistant, and the molded parts made from them by injection molding or the like have a smooth surface, so that the surface is difficult to decorate by printing, coating, deposition or the like or a surface treatment by gluing with the help of an adhesive Since polyateetal resins have a particularly low surface activity and no suitable solvent with an affinity for polyacetals is known, their surfaces are difficult to decorate and bond,. _{) 0} so that they are seldom used in the current state of the art for purposes requiring these treatments. Conversely, since polyacetal resin is excellent in mechanical properties, it is mainly used for mechanical parts or the like in many cases, so that decoration of its surface has not been required very often.

In recent times, however, there has been an increased trend in the use of plastics towards more versatile and sophisticated uses, with frequent is required to meet several requirements, for example the function and appearance or the Function and the ability to bond, although compatibility was not absolutely necessary up to now. The trend at the moment is that good surface machinability also in use is required of polyacetals.

It cannot be said that the possibility of improving the surface machinability of polyacetal resins has been intensively studied, but it is known that the surface machinability can be improved to some extent by treating the molded articles with an acidic solution or an antioxidant solution. As _bi- acid solutions, p-toluenesulfonic acid, camphor sulfonic acid, phosphoric acid, acidic ammonium sulfate and the like have been proposed, while mixtures of chromic acid and sulfuric acid have been proposed as acidic antioxidant solution.

It is considered the goal of treatment with these solutions to create a rough surface by means of chemical etching Surface of the molded parts made of polyacetal resins and at the same time reactive groups on part of the Polyacetaimoleküls form by the oxidizing effect of the solutions. While trying to see the effect of the To improve surface treatment in this method, problems and difficulties arise, e.g. B. an adverse change in the base material, i.e. the polyacetal resin, throughout Mass of molding through, cracking, etc. If, on the other hand, the treatment under conditions at which do not adversely affect the basic material, the effect is the Inadequate surface treatment so that good surface processing is not possible. Off For these reasons, no molded parts made of polyacetal resin are known which have sufficient surface workability for practical use exhibit.

It was an object of the present invention to provide a polyacetal resin composition excellent in surface machinability and heat resistance to make, from the molded parts with a roughened surface can be made, which are to Plating or coating are suitable.

The solution to this problem is a polyacetal resin composition, which consists of

a) 100 parts by weight of a polyacetal resin,

b) 2 to 35 parts by weight of a carbonate, phosphate or acetate of a metal from group II des Periodic table or a mixture of these salts,

c) 0.01 to 20 parts by weight of a polymer or copolymer of a compound from unsaturated polyesters. Alkyl esters of acrylic

acid and methacrylic acid, amides of acrylic acid and methacrylic acid, triallyl cyanurate, diallyl phthalate, vinyl acetate and divinylbenzene Group or a mixture of these polymers and copolymers and optionally d) a heat stabilizer, antioxidant, UV absorber, antistatic agent, nucleating agent and / or pigment

The inventive addition of a salt of a metal from Group II of the Periodic Table to The purpose of polyacetal resin is to facilitate the formation of a roughened surface suitable for surface processing. If a salt is a Metal of group II of the periodic table in the closed phase consisting of the polyacetal is dispersed, it can be easily decomposed and removed with an acid, leaving its traces as a roughened surface.

Examples of metals of group II of the periodic table which are suitable for the purposes of the invention, are calcium, magnesium, barium and zinc. Examples suitable salts are the carbonates, phosphates and acetates. Of these salts are the salts of Calcium, magnesium and barium are preferred and the carbonates of these metals are particularly preferred. Of these, calcium carbonate is again particularly preferred. Of the phosphates, the hydrogen phosphates are particularly preferred

In surface treatment, for example in Coating resins, the mirror-like nature of the surface and the adhesive strength are between the applied metal layer and the surface of the resin are often fundamentally important properties. Furthermore, it has good heat resistance during the Shaping required in certain cases unobserved. An investigation into the relationship between these properties and the mean particle size of the various salts of metals of group II of the periodic table showed that the metal salt worsened the mirror-like nature and the adhesive strength if the mean particle size was about 4.0 μm exceeds, and the adhesive strength and heat resistance deteriorate as the particle size is smaller than about 0.1 μπι. If the mirror-like texture the adhesive strength and heat resistance are taken into account at the same time, accordingly is the middle one Particle size of the salt of the metal from group II of the periodic table is preferably in the range of about 0.1 to 4.0 μπι, in particular in the range from about 0.5 to 2.0 μπι.

If the amount of the salt of the metal of group II of the periodic table is too small, a Improvement of the machinability of the surface cannot be effected. If the crowd is too big, be the mechanical properties of the polyacetal resin deteriorates; at the same time will improve the The machinability of the surface is greatly reduced, and the heat resistance during molding becomes also deteriorated. A consideration of this balance therefore shows that the amount of salt is preferably in the Range from about 2 to 35 weight percent per 100 parts by weight Polyacetal resin, with an amount in the range of about 2 to 25 parts by weight being particularly preferred.

In-depth studies of this polyacetal resin, d. H. various compositions with a polyacetal resin and various salts of metals Group II of the periodic table with a middle Particle size and in an amount in the above Areas mentioned have shown that when a molded part is etched with a suitable acid, d. H. one acidic solution or an antioxidant solution, crack formation

tion occurs in the molded part itself and the mirror-like nature and mechanical properties of the plated product will be greatly deteriorated if the acidic solution or antioxidant solution especially is strong, and that with insufficient regulation and

ίο Monitoring of the molding conditions from time to time Discoloration of the molded part can occur and streaks due to the decomposition gas generated by the thermal Decomposition of the polyacetal resin is formed during molding, sometimes the surface of the

Much can remain behind.

Ice was found to be the above Problems can be solved if the above-described polyacetal resin composition additionally contains a polymer or copolymer of a compound of the from unsaturated polyesters, alkyl esters of acrylic acid or methacrylic acid, amides of acrylic acid or Methacrylic acid, triallyl cyanurate, diallyl phthalate, vinyl acetate and divinylbenzene or a group Mixture of these polymers and copolymers is added.

As unsaturated polyester, products of the esterification of an unsaturated dicarboxylic acid or their mixture with a saturated dicarboxylic acid or a saturated or unsaturated monocarbon acid with a polyhydric alcohol or its Mixture with a monohydric alcohol can be used.

As unsaturated dicarboxylic acids used as acids for the manufacture of unsaturated polyesters maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, endomethylenetetrahydrophthalic acid and the like come into consideration. As saturated Dicarboxylic acids can, for example, o-phthalic acid, phthalic anhydride, isophthalic acid and terephthalic acid and adipic acid can be used. Mixtures of two or more of these acids are also suitable Acetic acid, propionic acid, butyric acid, benzoic acid, acrylic acid, methacrylic acid and mixtures of these acids can be used as monocarboxylic acids. the The above-mentioned carboxylic acids can also be used in the form of their alkyl esters, for example the methyl esters and dimethyl ester, can be used.

As polyhydric alcohols, for example, ethylene glycol, propylene glycol, butanediol, diethylene glycol kol, dipropylene glycol, glycerin and trimethylol propane be used. Suitable monohydric alcohols are, for example, methanol, ethanol and allyl alcohol.

The preferred unsaturated polyesters include, for example, esters that are isophthalic acid, maleic acid Contain anhydride and diethylene glycol.

The unsaturated polyester is often in the form of a mixture with in order to facilitate its thermosetting a crosslinking agent that contains reactive unsaturated bonds, for example a vinyl moiety nomeren or vinyl prepolymer containing an unsaturated residue of a vinyl group is used as Crosslinking agents are, for example, styrene, Λ-methylstyrene, vinyl pyridine, vinyl pyrrolidone and vinyl propionate

t, 5 When styrene, α-methylstyrene, vinylpyridine, vinylpyrrolidone, vinyl propionate or the like as a crosslinking agent are added, their amount is preferably in the range of about 20% to 100% of the weight of the

unsaturated polyester or the total weight of the unsaturated polyester and other compounds (As already mentioned, the amount is in such a range that the weight of the unsaturated polyester or the total weight of the unsaturated polyester and other compounds about 20 parts by weight or less per 100 parts by weight of the polyacetal resin). When used together with a Crosslinking agent includes the amount of unsaturated polyester the amount of crosslinking agent used a.

When in the component (c) of the resin composition according to the invention, the unsaturated polyester with others Compounds is copolymerized or mixed, their proportions can be chosen at will.

The alkyl esters of acrylic acid or methacrylic acid are those with 1 to 5 carbon atoms, preferably with 1 up to 2 carbon atoms, used in the alkyl radical

The above component (c) which is the polyacetal resin (a) together with the salt (b) of the Metal of group II of the periodic table is to be added, thus represents a mandatory part of the Polyacetal resin composition according to the invention. The purpose of adding the component (c) becomes briefly summarized again below: it is added to prevent cracking in molded parts, even if these are etched with a particularly strong acidic solution or oxidant solution; she will also added in order to prevent deterioration in the heat distortion resistance during shaping prevent that can occur if a salt of a metal of group II of the periodic table dem Polyacetal resin is added.

The reason by which cracking during etching can be prevented is not clear _t5 clarified, but it is assumed that the addition of a salt of a metal of group II of the periodic table to the polyacetal resin, the mass obtained is rigid and has increased internal stresses When the aforementioned component (c) is added, the internal stress becomes less or disappears as a result of the plasticizing action of component (c), so that cracking can be prevented.

The amount of the component (c) used in the invention differs depending on v, the kind of the compound, but it is preferably in the range of about 0.01 to 20 parts by weight per 100 parts by weight of the polyacetal resin, one being Amount in the range of about 0.01 to 15 parts by weight is particularly preferred. If the amount is less than 0.01 part by weight, the above-mentioned effect cannot be obtained. If the amount exceeds about 20 parts by weight, the overall strength and other characteristic properties of the resin composition are deteriorated.

The polyacetal resin used for the purpose of the invention may be a homopolymer; H. a through Polymerization of formaldehyde or trioxane (including the polymers that have been subjected to a treatment to stabilize the end groups) or a Copoiymerisat of be two, three or more monomers obtained by copolymerization of trioxane with comonomers such as cyclic ethers, cyclic acetals or the like. Has been obtained. f, -,

The polyacetal resin composition according to the invention can contain various additives which are usually used in f'olyacetal resins are used, for example heat stabilizers, antioxidants, UV absorbers, Antistatic agents, nucleating agents and pigments can be added.

For the preparation of the polyacetal resin compositions according to the invention, the constituents are preferred with an apparatus commonly used for kneading resin melts such as a Kneader, roller mixer or extruder, mixed to exclude oxygen and the environment of the To protect the workplace, the use of an extruder is particularly recommended.

The mixing temperature is not lower than the melting point of the polyacetal resin used. This arises from the need to mix the polyacetal resin uniformly in the molten state. The upper limit of the temperature is usually determined by the resistance of the polyacetal resin used to thermal decomposition. The mixing is usually conducted at a temperature of about 25O ⁰ C or lower, preferably at about 230 ⁰ C or lower performed

The heat stabilization ir -.- i prevention of Component (c) added to crack formation, e.g. B. a unsaturated polyester, can be admixed directly as a polymer or copolymer or in the form of a Monomers or prepolymer added and then polymerized in an extruder. In case of The latter method is preferable to thermosetting polymers.

In order to produce a resin mass of uniform quality, it is advisable to combine the individual components premix with a drum mixer or Henschel mixer. It is also used to stabilize the Appropriate feedstock in an extruder to use the polyacetal resin in powder form. These However, conditions are not mandatory.

In the method described above, in which a monomer or a prepolymer is added is, the temperature of premixing is preferably maintained at such a value that none Polymerization is caused.

In the above process, is added at the cn monomer or a prepolymer, a temperature of about 190 ⁰ C and a duration of about 1 to 10 minutes as a sufficient heating conditions for their polymerization, for example, are required, although the conditions vary depending on the type of the monomer or prepolymer may vary. These conditions can be achieved in most cases by combining the temperature and time usually used for mixing a polyacetal resin composition with the aid of a conventional extruder (depending on the extrusion speed), with no additional heating means being required. In the context of the invention, the heating means itself is not subject to any limitation.

It is also possible to add a polymerization initiator to the polyacetal resin composition.

The heating mentioned above polymerizes the added polymer or prepolymer There are currently numerous methods of ensuring that no residue remains unreacted remain. A simple method here is to do so by the smell of the mixture immediately after the Heating and extrusion (usually with the formation of granules) should be carried out. Another suitable method consists in putting the granules in a solvent

Immerse and use infrared spectroscopy to check that any unreacted material has been extracted.

The granules of the polyacetal resin composition prepared by the method described above according to the invention is then by conventional methods, for example by injection molding, extrusion or Pressing, processed into any desired molded parts. The molded product has excellent Machinability of the surface. It can be used to roughen the surface with a suitable Solution treated and then electroplated or coated in a known manner (see for example Modem Plastics Encyclopedia 1967, pp. 1019-1021).

The invention is further illustrated by the following examples: but is used for roughening the Surface of the molded parts and the subsequent plating or coating here no protection is sought.

Examples I to 13
and Comparative Examples 1 and 2

100 parts by weight of a commercially available acetal homopolymer were with 8.7 parts by weight of finely powdered calcium carbonate of a mean particle size of 1.25 μτη and that serving as component (c), in Table I mixed in the amount mentioned there in a rotating drum. The mixture was kneaded and granulated with the aid of an extruder set at 190.degree. The thermal stability measured. A 3.2 mm thick plate was used as a test specimen from the injection molding process Granulate produced.

The plate was degreased with 1.1,1 -Trichloräthan and then etched by being in a solution of 96% sulfuric acid at 40'C for 8 minutes. 85% phosphoric acid and water was immersed in a weight ratio of 40:25:35.

The etched plate was then plated in the usual manner by strength aqueous hydrochloric acid solution and was finally immersed in a chemical plating solution based on nickel and then immediately electroplated during a certain time in a pretreatment solution for the plating of plastics, then in a IO ^u /. The average thickness of the deposited layers was 40 μm for copper, 10 μm for nickel and 0.1 μm for chromium. The properties of the plated product thus obtained are shown in Table I. They were determined using the following methods:

I) Adhesion Strength or Peel Strength of Clad Product:

Two parallel lines were drawn 10 mm apart on the plated surface, and

i idf iai.iifi.1

2)

Break lines were peeled off at right angles to the flat plate to measure the force required to tear it off.
Appearance of the plated product:
Under a light source of 300 lux or more, the appearance was examined with the naked eye from a distance of 60 cm from the surface of the test piece. The criteria for the evaluation r; v, d are given in the footnote to Table 1.

As the results in Table I show, the polyacetal resin composition according to the invention has improved Heat resistance and excellent platability.

T.ibello

\ t-'r

example
I.

roUaeeialhar /

ti Iomopo! ymcris; iU

Gew-Teüe

(; ilciumcarbon; it
(mean particle size
1.25 in ι. Parts by weight
link

(Parts by weight)
Heat resistant keu
(Footnote 1)

remaining non-skimmed
link

Detection method (solution mine extraction or smell

Running out of the plated
Product (footnote 2)

Haiiic> iigk £; i des

-iatiienen product. Vmm

8.7

100

100

8th."

ίο »)

100

U.N- Meihyl- Ethyl methyl eesaturated acrylate acrylate meth- Poly acrylate ester O 0.87 0.01 0.76 0.87 Δ © O O O (Metha (Metha (Metha (Metha nol / nol) nol) noil Toluene! Γ-

2.3

Table I (continued) 29 example 42 744 7th 10 9 9 5 100 100 100 Polyacetal resin 8.7 S. 8.7 Parts by weight 8.7 6th 100 Calcium carbonate 100 (Average particle size Methacrylic 8.7 Diallyl 1.2 $ y.m). Parts by weight Ethyl meth- 8.7 amide phthalate link rtcrylat (Foot Triallyl cyan Note 3) Acrylamide 0.87 urate (foot 0.87 0.01 © Note 3) O (Parts by weight) O Heat resistance - (.. 10 - (Footnote 1) - 0.87 (Odor) O (Cieruch) p'stliche not implemented (Methanol) © Detection method (solution medium.extraction or O (Odor) O Cieruch) O (Cieruch) Appearance of the plated 2.1 1.6 Product (footnote 2) 1.6 O Adhesion strength of the O plated product. N / mm 1.8 Table 1 (continued) 2.0

Example 10

12th

Polyacetal resin 100 100 100 100

Ciew. Parts

Calcium carbonate 8.7 8.7 8.7 8.7

(mean particle size 1.25 μm). Parts by weight link

Vinyl acetate Divinylbenzene Polyvinyl unsaturated acrylic acetate polyester amide (Footnote 4 / 0.87 0.87 0.87 0.50 0.40 O O © ©

(Odor)

2.1

2.2

(Odor)

2.1

(Parts by weight)

Heat resistance (footnote 1)

remaining unreacted

link Detection method (smell)

(Solvent extraction or smell)

Appearance of the plated O Product (footnote 2) Adhesion strength of the plated 1.7 Product. N / mm

') © Injection molding is perfectly possible under normal conditions.

Injection molding is possible without practical problems, but the range of suitable conditions is somewhat narrow.

Δ At the time of injection molding, streaks are formed by decomposition of the resin.

x extrusion is impossible.

² ) Appearance was evaluated with the naked eye according to the following criteria: ○ Mirror surface with no cracks.

Δ Dark image, but the face is reflected; no cracking.

x No reflected image of the face; Crack formation, in the following tables, the same characters have the same symbols Meanings as described above.)

³ ) 03 parts by weight (Example 8) and 0.04 part by weight (Example 9) of 2J-dimethyl-2J-di (tert-butylperoxy) -hexane was added as a polymerization initiator.

^Λ ) Degree of polymerization 200.

Examples 14-17 and Comparative Examples 3 and 4

100 parts by weight of the acetal homopolymer used in the previous examples were 8.7 ■> Parts by weight of magnesium carbonate (mean particle size 2 to 3 μm), barium carbonate (mean particle size 2 μm), barium acetate (mean particle size 3 μπι) or Calc'-Jmhydrogenphosphat (mean particle size 2 to 3 μιη) instead of calcium carbonate in and as a reactive compound a certain amount of an unsaturated polyester (mixture of 70 Parts by weight of a polyester prepolymer made from isophthalic acid, maleic anhydride and diethylene glycol [molar ratio 1: 1: 2], medium polymerisation ι ', tion degree 10, and 30 parts by weight of styrene as cross-linking

mixture) in the drum mixer, whereupon the Mixture kneaded and granulated in the same way as described above in the VxTuder became.

The heat stability of the granules was measured. From the granules, a plate was placed on the plate in Example 1 prepared and plated in order to study the properties of the plated product.

The heat resistance of these polyacetal resin compositions and the properties of the plated products are mentioned in table 2.

(All of the above metal salts were chemically pure. The barium acetate was after Used to grind in the mortar, while the other salts are used in the form in which they were presented became.)

Table 2 Comparative Example 14 Comparative Example 15 Example 16 Example 17 example 3 example 4 100 100 100 100 100 100 Polyacetal resin Parts by weight 8.7 8.7 - - - - Magnesium carbonate (mean particle size 2 to 3 μίτι), parts by weight - - 8.7 8.7 - - Barium carbonate (mean particle size 2 μπι), parts by weight - - - - 8.7 - Barium acetate (mean particle size 3 μίτι), parts by weight - - - - - 8.7 Calcium hydrogen phosphate (mean particle size 2 to 3 μπι), parts by weight - 8.7 - 10.0 0.15 0.87 unsaturated polyester, Parts by weight violent Well violent Well Well Well Extrudability Foam Foam X O X O O O Heat resistance - O - O O O Appearance of the plated Product - 1.8 - 1.7 1.6 1.7 Adhesion strength of the deposited metal layer (N / mm)

Examples 18-20 and Comparative Examples 5 and 6

100 parts by weight of the above acetal homopolymer were mixed with 11.1 parts by weight of calcium carbonate with the mean particle sizes given in Table 3 and 1.1 parts by weight of a commercially available one mixed unsaturated polyester. The resin composition obtained was based on that described in Example 1 Way plated. The properties of the plated products were determined

The properties of the clad products are shown in Table 3.

Table 3

Comparative example 5 *)

Example 18 19

20 **)

Comparative example 6

average Particle size of the calcium carbonate, etc.

Heat resistance

0.08

1.0

1.25 ©

3.6

5.0 ©

f'οι, set / unc:

Appearance
Adhesion Strength, N / mm

Comparative example

example 5 *) ^

19th

O
2.0

20 * ·)

Δ
1.5

Comparative example 6

1.0

*) Extrusion was impossible.
**) The product is suitable for applications where good looks are not absolutely necessary.

Examples 21 to 23 and Comparative Example 7

The same etched plate as in Table 3 was used. After the etching, the latte was washed well with water, dried in the air, with an ^{ani r} ichiiiiüe! on AcryiiiHi / 1μμ. · <bii and then fired at 150 ° C for 30 minutes. The adhesive strength of the applied paint film was tested by pressing a pressure-sensitive adhesive strip onto the surface to which grid cuts with squares of 3.2 mm edge length had been applied, and then tearing off the adhesive strip. The results are given in Table 4.

Rush in 4

example 1.25 3.6 Comparative 2! example 7 average Particle size of calcium 1.0 O 5.0 carbonates. y.m iilän / end glittering Adhesion strength of the paint film (G) X (Ί lan / uliinzend not glittering

Criteria for evaluation at 11 11tiotiy kei t slcsl.

no change.

Partial loosening at the square miles. 'The proportion of the detached quadrille is> t 20 odi- * λ ■' ■ lits t all squares detach.

Examples 24 to 27 and Comparative Examples 8-10

The same calcium carbonate as in the example! (mean particle size 1.25 μίτι) was used and the plate is plated in the manner described in Example 1, but the amount of calcium carbonate varies as indicated in Table 5. Furthermore, the unsaturated polyester was used in an amount corresponding to 10% of the Calcium carbonate corresponded to (parts by weight). added. The results are given in Table 5.

Table 5

Comparative Comparative Example 24 Example 25 Example 26 Example 27 Comparative Example 8 Example 9 Example 10

Polyacetal resin
Parts by weight
Calcium carbonate
i mean particle size
1.25; ιτη)
Parts by weight

unsaturated polyester.
Part by weight
Heat resistance

0.1

100
8.7

0.87

! 7.6

1.76

25.0

2.5

42.9

4.3

15 16

continuation

Comparative Comparative Example 24 Example 25 Example 26 Example 27 Comparative example 8 example 9 example 1

Properties before 68.6 68.6 67.7 63.7 58.8 56.9 Plate 18th 17th 16 12th 9 8th Tensile strenght,
N / mm * Elongation (between 103 103 102 102 101 100 the terminals,%) Flexural strength, 0.6 0.6 0.5 0.5 0.4 0.4 N / mno (6) (6) '5) (5) (4) (4) Notched Izod toughness. N m / cm X X O O O O (kg cu / cm) Appearance of the 0.7 0.9 1.5 2.3 2.3 2.0 plated product Adhesion strength of the deposited metal layer. N / mm

Note: In the case of Comparative Example 10, the resin was decomposed during extrusion.

Examples 28 to 31

and
Comparative Examples 11 and 12

The experiment described in Examples 25 to 27 and Comparative Example 8 was repeated, except that ei Acetal copolymer was used. The results obtained are shown in Table 6.

Table 6

Comparative example 29 30th 31 Comparison example Il 28 100 100 100 example ii Polyacetal resin 100 100 100 (Copolymer) Parts by weight 17.6 25.0 33.3 Calcium carbonate 0 8.7 42.9 (mean particle size 1.25; j.m), parts by weight 1.76 2.50 3.33 unsaturated polyester. 0 0.87 4.29 Parts by weight © © O Heat resistance © ® O O Δ Δ Appearance of the plated O O X Product 2.1 1.8 1.5 Adhesion strength of the 0.2 1.3 1.0 deposited metal layer (N / mm!

U e is pie le 32 to 34

and
Compared to example 13

The experiment described in Example 25 was repeated, except that the amount of unsaturated l'ol \ este was varied. The results obtained are given in Table 7.

Table 7

example 33 34 Comparison 32 100 100 example 13 Polyacetic resin 100 100 Parts by weight 8.7 8.7 Calcium carbonate (mean particle size 8.7 8.7 1.25 am), parts by weight 10 15th unsaturated polyester, parts by weight 0.87 O O 25th Heat resistance © 58.8 55.9 X Tensile strength, N / mm ² 63.7 13th 13th 51 Elongation (between the clamps), ⁰ / » 12th 88.3 83.4 14th Flexural strength, N / mm ² 102 72.6 Notched Izod Impact Strength 0.4 0.3 Nm / cm 0.5 (4) (3) 0.2 (kg cm / cm) (5) (2)

Example 35 bis

and Comparative Examples 14 to

An identical 3 mm thick plate as in Example 1 was plated in the manner described in Example 1, wherein however, the composition of the etching solution was varied as shown in Table 8. The adhesive strength of the deposited metal layers are given in Table 8.

Table 8

example
35 36

37

38

39

40

Comparative example
14 15 16

17th

18th

96% sulfur 40/25 30/35 32/10 25/55 45/0 60/0 20/0 10/15 20/15 76/24 80/0

acid / 85%

phosphoric acid

(Parts by weight) *)

optimal 8 8 70 3 50 4 800 1000 600 1 1

Etching time

(40 C x

Minutes)

Adhesion strength, 2.2 2.0 1.6 2.0 1.5 1.6 1.0 0.4 l.i 1.9 1.4

*) If the sum of the parts by weight was less than 100 parts by weight, W.isser was added until the total weight was 100 parts by weight reached.

Example 41

An equal 3 mm thick plate as in Example 29 for 12 minutes at 40 ⁰ C in a Ät / Iösung the composition mentioned below was dipped and then electroplated in the manner described in Example 29. The deposited metal coating had an adhesive strength of 1.3 N / mm.

Composition of the etching solution

96% sulfuric acid 55 parts by weight

Potassium dichromate 4 parts by weight

Water 45 parts by weight

As the above examples show, the polyacetal resin compositions according to the invention are excellent in heat resistance, and by etching the molded articles made therefrom, products having excellent surface machinability are obtained, so that the field of application of the resins is further expanded. For example, they may be required to be used as a substitute for metals in the form of parts in which both functional al ¹ * and decorative properties. With these polyacetal resin compositions, a very strong weight reduction and cost savings are achieved.

Claims (1)

Claims; 1. Polyacetal resin compound with excellent heat resistance and machinability of the surface marriage, consisting of a) 100 parts by weight of a polyacetal resin, b) 2 to 35 parts by weight of a carbonate, phosphate or acetate of a group II metal of the periodic table or a mixture of these salts, c) 0.01 to 20 parts by weight of a polymer or copolymer of a compound from unsaturated polyesters, alkyl esters of acrylic acid and methacrylic acid, amides of acrylic acid and methacrylic acid, triallyl cyanurate, Diallyl phthalate, vinyl acetate and divinylbenzene, or a mixture thereof these polymers and copolymers and optionally d) a heat stabilizer antioxidant, UV absorber, antistatic agent, crystal nucleating agent and / or pigment